银联手机支付(.Net Csharp)，3DES加密解密，RSA加密解密，RSA私钥加密公钥解密，.Net RSA 3DES C#

前段时间做的银联支付，折腾了好久，拼凑的一些代码，有需要的朋友可以参考，本人.Net新手，不保证准确性！

这个银联手机支付没有SDK提供，技术支持也没有.Net的，真心不好搞！

RSA加解密，这里有个麻烦就是私钥加密/公钥解密；

3DES加解密，这里有个问题是所用的密钥长度不一样，银联向我们发送报文时密钥用32字节长度的，我们.Net最多用24字节，办法是直接取密钥前24字节就行了；

下面是RSA算法的加解密，用到一个BigInteger类(http://www.codeproject.com/csharp/biginteger.asp)：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography;

namespace Kad.ThridParty.ChinaPayWap
{
    /// <summary>
    /// 非对称RSA加解密，私钥加密/公钥解密
    /// 仅用于银联Wap支付报文收发
    /// By : EnVon(E旺) 2013-08-20
    /// </summary>
    internal class RSAHelper
    {

        /// <summary>
        /// RSA加密（用私钥加密哟）
        /// </summary>
        /// <param name="key">私钥</param>
        /// <param name="data">待加密的数据</param>
        /// <returns></returns>
        public static byte[] Encrypt(String key, byte[] data)
        {
            //由密钥xml取得RSA对象
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            rsa.FromXmlString(key);
            //取得加密时使用的2个参数
            RSAParameters par = rsa.ExportParameters(true);
            BigInteger mod = new BigInteger(par.Modulus);
            BigInteger ep = new BigInteger(par.D);
            //计算填充长度
            int mLen = par.Modulus.Length;
            int fLen = mLen - data.Length - 3;
            //组建bytes
            List<byte> lis = new List<byte>();
            lis.Add(0x00);
            lis.Add(0x01);//兼容java
            for (int i = 0; i < fLen; i++) lis.Add(0xff);
            lis.Add(0x00);
            lis.AddRange(data);
            byte[] bytes = lis.ToArray();
            //加密就这么简单？
            BigInteger m = new BigInteger(bytes);
            BigInteger c = m.modPow(ep, mod);
            return c.getBytes();
        }

        /// <summary>
        /// RSA解密（用公钥解密哟）
        /// </summary>
        /// <param name="key">公钥</param>
        /// <param name="data">待解密的数据</param>
        /// <returns></returns>
        public static byte[] Decrypt(String key, byte[] data)
        {
            //由密钥xml取得RSA对象
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            rsa.FromXmlString(key);
            //取得解密时使用的2个参数
            RSAParameters par = rsa.ExportParameters(false);
            BigInteger mod = new BigInteger(par.Modulus);
            BigInteger ep = new BigInteger(par.Exponent);
            //解密？
            BigInteger m = new BigInteger(data);
            BigInteger c = m.modPow(ep, mod);
            byte[] bytes = c.getBytes();
            //去掉填充域（头部可能填充了一段0xff）
            byte flag = 0;
            for (int i = 1/*我从1开始啦*/; i < bytes.Length; i++)
            {
                if (bytes[i] == flag && i != (bytes.Length - 1))
                {
                    byte[] retBytes = new byte[bytes.Length - i - 1];
                    Array.Copy(bytes, i + 1, retBytes, 0, retBytes.Length);
                    return retBytes;
                }
            }
            return bytes;
        }

        /// <summary>
        /// 取得证书私钥
        /// </summary>
        /// <param name="pfxPath">证书的绝对路径</param>
        /// <param name="password">访问证书的密码</param>
        /// <returns></returns>
        public static String GetPrivateKey(string pfxPath, string password)
        {
            X509Certificate2 pfx = new X509Certificate2(pfxPath, password, X509KeyStorageFlags.Exportable);
            string privateKey = pfx.PrivateKey.ToXmlString(true);
            return privateKey;
        }

        /// <summary>
        /// 取得证书的公钥
        /// </summary>
        /// <param name="cerPath">证书的绝对路径</param>
        /// <returns></returns>
        public static String GetPublicKey(string cerPath)
        {
            X509Certificate2 cer = new X509Certificate2(cerPath);
            string publicKey = cer.PublicKey.Key.ToXmlString(false);
            return publicKey;
        }

    }
}

下面是3DES的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace Kad.ThridParty.ChinaPayWap
{
    /// <summary>
    /// 对称加密3DES加解密，代码来源于网络
    /// </summary>
    internal class TripleDESHelper
    {

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="toEncrypt">要加密的字符串，即明文</param>
        /// <param name="key">公共密钥</param>
        /// <param name="useHashing">是否使用MD5生成机密秘钥</param>
        /// <returns>加密后的字符串，即密文</returns>
        public static string Encrypt(string toEncrypt, string key, bool useHashing)
        {
            try
            {
                byte[] keyArray;
                byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

                if (useHashing)
                {
                    MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                    keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                }
                else
                    keyArray = UTF8Encoding.UTF8.GetBytes(key);

                TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

                tdes.Key = keyArray;
                tdes.Mode = CipherMode.ECB;
                tdes.Padding = PaddingMode.PKCS7;

                ICryptoTransform cTransform = tdes.CreateEncryptor();
                byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                return Convert.ToBase64String(resultArray, 0, resultArray.Length);
            }
            catch
            {

            }
            return string.Empty;
        }
        public static string Encrypt(byte[] toEncryptArray, string key, bool useHashing)
        {
            try
            {
                byte[] keyArray;
                //byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

                if (useHashing)
                {
                    MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                    keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                }
                else
                    keyArray = UTF8Encoding.UTF8.GetBytes(key);

                TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

                tdes.Key = keyArray;
                tdes.Mode = CipherMode.ECB;
                tdes.Padding = PaddingMode.PKCS7;

                ICryptoTransform cTransform = tdes.CreateEncryptor();
                byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                return Convert.ToBase64String(resultArray, 0, resultArray.Length);
            }
            catch
            {

            }
            return string.Empty;
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="toDecrypt">要解密的字符串，即密文</param>
        /// <param name="key">公共密钥</param>
        /// <param name="useHashing">是否使用MD5生成机密密钥</param>
        /// <returns>解密后的字符串，即明文</returns>
        public static string Decrypt(string toDecrypt, string key, bool useHashing)
        {
            try
            {
                byte[] keyArray;
                byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);

                if (useHashing)
                {
                    MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                    keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                }
                else
                    keyArray = UTF8Encoding.UTF8.GetBytes(key);

                TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
                tdes.Key = keyArray;
                tdes.Mode = CipherMode.ECB;
                tdes.Padding = PaddingMode.PKCS7;

                ICryptoTransform cTransform = tdes.CreateDecryptor();
                byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                return UTF8Encoding.UTF8.GetString(resultArray);

            }
            catch
            {

            }
            return string.Empty;
        }
        public static string Decrypt(byte[] toEncryptArray, string key, bool useHashing)
        {
            try
            {
                byte[] keyArray;
                //byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);

                if (useHashing)
                {
                    MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                    keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                }
                else
                    keyArray = UTF8Encoding.UTF8.GetBytes(key);

                TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
                tdes.Key = keyArray;
                tdes.Mode = CipherMode.ECB;
                tdes.Padding = PaddingMode.PKCS7;

                ICryptoTransform cTransform = tdes.CreateDecryptor();
                byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                return UTF8Encoding.UTF8.GetString(resultArray);

            }
            catch
            {

            }
            return string.Empty;
        }

    }
}